When you're in your Markdown snipt, adding this custom tag will automatically embed a YouTube
video with the desired dimensions:

[[youtube-{video_id}-{width}x{height}]]

Where {video_id} is replaced with something like K7vU2cDIyjU (you can grab the ID in the URL
of any YouTube video). {width} would be replaced with a width value like 688 and {height} with something like
387.

For Vimeo video:

[[vimeo-{video_id}-{width}x{height}]]

Note: embedding videos makes list-view of snipts sometimes chop off half the video. If you have
a blog post that you'd like to force an "always expanded" view in the list-view, simply add the
tag "snipt-expand" to the snipt.